Damage to public infrastructure, including roads and bridges, is expected to cost millions of dollars to repair.

Tasmanian Premier Will Hodgman has toured flood-affected areas and thanked emergency services and volunteers for their efforts.

The Government has offered immediate financial support to those affected.

"By no means are we through this, but there has been good news in so far as reports of weather conditions are concerned, but my message to Tasmanians is that they need to remain especially vigilant," Mr Hodgman said.

Spirit of Tasmania services to resume

TasPorts expects Spirit of Tasmania services to resume within the coming days at Burnie if the Port of Devonport can not be used.

Submerged boats and other debris need to be removed from the Mersey River, before the Spirit and freight vessels can return to Devonport.

TT-Line has cancelled sailings from Devonport and Melbourne, but additional voyages have been scheduled on Sunday for affected passengers.

TasPorts chief operating officer Anthony Donald said the Spirit was too long for Bell Bay, making Burnie the obvious choice.

"We have assessed the infrastructure requirements in Burnie and believe that it is appropriate," he said.

"We're probably looking at it [being] 24 to 48 hours."

Authorities are urging people not to take their boats out on inland waterways due to the flooding.

Hydro Tasmania has warned some of its storages are overflowing and could suck watercraft into spillways.